A. The ball remains at a constant velocity until it reaches about .80 seconds, when it increases in velocity but then remains at a constant higher velocity.
B. Graph A is the correct graph. Graph B cannot be correct because as the ball increases in velocity, getting farther away from the initial position at a greater speed, the slope of the graph decreases. The decreasing, but positive slope would indicate that the ball had slowed down is moving away from it's initial position at a slower velocity. Graph C is wrong because it skips from one point to another which is impossible for an object to do as far as position goes. Graph A shows the correct constant slope and then increases at around .80 seconds.
C. Graph D is the correct graph. Graph E is incorrect because the object's initial velocity is constant, therfore should have a constant slope, or a 0 slope. Graph E begins with a positive slope which is showing position rather than velocity. Graph F starts off correct but as the ball increases in speed the graph proves to be incorrect. The ball does increase its velocity at one point but then remains at that velocity for the rest of its journey. Graph D is correct by showing that the velocity is constant showing a 0 slope, and by then skipping to a higher velocity with still a 0 slope.